Methods and apparatus for bridging a well conduit



Aug. 12, 1969 METHODS AND APPARATUS FOR BRIDGING A WELL CONDUIT FiledApril 14. 1967 5 Sheets-Sheet l I W 2 W M Y JO 4 E Z M .E 0 t m m d wa WM w V} B ZYAKEI H 4\\\\\\\ a 52; N N d.

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I H. J. HART ETAL- METHODS AND APPARATUS FOR BRIDGING A WELL CONDUITFiled April 14, 1967 5 Sheets-Sheet 2 Aug. 12, 1969 J. HART ETAL METHODSAND APPARATUS FOR BRIDGING A WELL CONDUIT I Filed April 14. 1967 3Sheets-Sheet 5 5 3 5 2 6 5 3 2 Z 9 I 7 7 Wm M ii $5 2 y N 5? a f m Z w5% im J f M w w MM M Z w AA J// a mflm p fl Ir, 0,1. N 0 457/635 /0 2a09/ Z ymmmiwwg y H fi W U W Z 2% i \\\/V|/ 7 5 j c :5 7 M J 4 0 r 04 366 2 7 m fix? w 4.4 l

ATTORNEY United States Patent U.S. Cl. 166-285 16 Claims ABSTRACT OF THEDISCLOSURE Methods and apparatus for plugging a well conduit, eithercased or open hole. An inflatable packer can be lowered into the wellthrough tubing and then expanded to several time its lowering size toeffect a seal against the well conduit. The expanded packer istemporarily vented so that well fluid can pass from one side of thepacker to the other as a cementitious material is deposited on top ofthe packer and allowed to harden. After the material has hardened, thevent can be closed. The venting procedure prevents produced fluids fromdisturbing the packer or the cementitious material as the plug is beingformed.

The present invention concerns new and improved methods and apparatusfor forming a pressure bridge or plug in the well conduit, either casedor open hole. More specifically, the present invention concerns new andimproved methods and apparatus for effectively plugging a well conduitbelow open tubing extending into the well conduit.

It is often desirable to form a pressure bridge or plug in a well casingfor preventing fluid flow therein in either longitudinal direction. Thiscan be accomplished in a conventional manner by lowering a device havingan expansible sealing element into the well and expanding the sealingelement against the surrounding well wall. In some cases, however, arelatively small size pipe or tubing may have been placed within thewell to extend downwardly from the earths surface into the well, and thepressure bridge or plug must be formed at a setting point below thelowermost end of the tubing.

In will be apparent that the relatively small bore size of the tubingplaces certain restrictions on the manner in which the plug can beformed and types of equipment which can be used. Of course, the tubingcan be removed from the well, a conventional bridging plug set and thetubing reinserted into the well. However, this procedure can betime'consuming and expensive and can be avoided in accordance with thepresent invention, which permits the bridge to be placed inthe wellwithout removing the tubing.

Typical prior art devices which are directed to this end are disclosedin United States Patent Nos. 2,815,817 and 2,618,344. Accordingly tothese disclosures, a cementitious material can be displaced into aninflatable bag and allowed to harden so that the bag bridges the wellbore. Accordingly to another United States Patent No. 3,208,530, aribbed basket can be lowered into the well bore and a fusible materialplaced on top of the basket which can harden to form a plug.

The prior art devices have a common shortcoming, viz, that during thelength of time required for the plug to form into a hardened masscapable of withstanding differential pressure, a zone below the plug maybe producing fluid. The produced fluid can form channels either aroundthe bag or through cementitious material placed on top of the bag, orboth. The channels can provide "ice fluid communication paths throughthe plug which destroy its effectiveness; the plug will not holdpressure.

An object of the present invention is to provide new and improvedmethods and apparatus for forming a pressure bridge in a well conduit.

Another object of the present invention is to provide new and improvedmethods and apparatus for forming a pressure bridge in a well conduit ata point below the lowermost end of a much smaller well conduit andwithout removing the smaller conduit from the well.

Another object of the present invention i to provide new and improvedmethods and apparatus for forming a pressure bridge in a well conduit ina manner which prevents any channeling of fluids through the bridge asit is formed so that it will effectively hold fluid pressuredifferentials which may be imposed upon it.

Yet another object of the present invention i to provide new andimproved methods and apparatus for forming a pressure bridge in a wellconduit and which are simple to perform and reliable in operation andwhich are effective in providing a means for preventing fluid flow ineither direction in the well conduit.

Briefly described, a method in accordance with the present inventionincludes the manipulative steps of lowering an expandable packer througha tubing string and into a well conduit below the lower end of thetubing string and then expanding the packer to several times itslowering size to form a bridge in the well conduit. The expanded packeris temprarily vented so that well fluids can pass longitudinallytherethrough. With the packer vented, the method is further practiced bydeposting a cementitious material on top of the packer and allowing thecementitious material to harden and then closing off the vent. Theventing procedure prevents the development of any pressure differentialsacross the packer which may otherwise force fluid through the plug andform channels therethrough.

Briefly described, apparatus for plugging a well in accordance with thepresent invention includes a support adapted for lowering into a wellbore. An inflatable packer means on said support is adapted to have awide range of expansion upon inflation thereof, and means selectivelyoperable from the earth surface are provided for inflating the packermeans to expand it into sealing engagement with the surrounding wellconduit wall. A vent passageway extends from a location below to alocation above the packer means to provide a fluid communiction paththerethrough so that well fluids can temporarily pass through theinflatable means in its inflated condition. Means are also provided fordepositing a cementitious material on the top side of the packer meansin its expanded condition to increase the overall length of the plug inthe well bore and thereby increase its effectiveness in holdingpressure. Also, a valve means is provided for selectively closing offthe vent passageway when desired.

The invention has other objects and advantages which will becomeapparent in connection with the following detailed description. Thenovel features of the present invention being set forth withparticularity in the appended claims, the present invention, both as toits organization and manner of operation, may best be understood by wayof illustration and example of certain embodiments when taken inconjunction with the accompanying drawings, in which:

FIGURE 1 is a longitudinal sectional view of one embodiment of anapparatus for practicing the present invention with parts in retractedpositions for lowering FIGURE 3 is a sectional view of various parts ofthe apparatus of the present invention which remain in the well conduitto form a plug therein;

FIGURE 4 is a longitudinal sectional view of another embodiment of anapparatus for practicing the present invention with parts in retractedpositions for lowering into a well;

FIGURE 5 is a view similar to FIGURE 4 with various parts in setpositions for plugging a Well conduit;

FIGURE 6 is a sectional view of the second embodiment apparatus whichremains within the well conduit to form a plug therein;

FIGURE 7 is a longitudinal sectional view of yet another embodiment ofan apparatus for practicing the present invention with parts in relativepositions for lowering into a well;

FIGURE 8 is a sectional view of the lower portion of the apparatus ofFIGURE 7 with the packer expanded to plug a well conduit; and

FIGURE 9 is a view similar to FIGURE 8 but with various parts operatedfor depositing cementitious material on the top side of the plug.

One embodiment of an apparatus for practicing the present invention isshown in FIGURE 1 and includes a packer section A coupled to an anchorsection B which is, in turn, coupled to a pump section "C. The entiretool can be suspended in the well bore on a running-in string in theform of an armored electrical cable 10.

The packer section A includes a support tube 11 having a fluidpassageway or vent 12 extending longitudinally in an axial directiontherein from lower side ports 13 to an upper end surface of the supporttube, An inflatable, expansible bag or packer element is mounted aroundthe support tube 11 with its lower end connected to a sleeve 15 bysuitable clamps 16, seal elements 17 preventing fluid leakage betweenthe sleeve 15 and the support tube 11. The upper end portion of the bag14 is also secured by a clamp 18 to an upper sleeve 20 which sealinglyengages the support tube 11. Longitudinal or spiral folds (not shown)can be formed in the bag 14 to minimize its retracted diameter and topermit a wide range of expansion during inflation. The bag 14 can beappropriately made of a suitable material such as neoprene impregnatedDacron cloth which is impermeable as well as readily pliable. The uppersleeve 20 can be slidable on the support tube 11 so as to accommodatechanges in vertical length of the bag 14 during its expansion. Aninflation passageway 21 can extend in an axial direction in the supporttube 11 from its upper end surface to a lateral port 22 which opens intothe interior of the bag 14.

The anchor section B is suitably coupled to the packer section A bythreads 24 or the like. The anchor section includes a generally tubularhousing 25 having at least three radially directed recesses 26 whichextend into an elongated central chamber 27, the recesses 26 eachreceiving anchor arms 28 which can be pivotally mounted on pins 29. Theanchor arms have gripping surfaces 30 at their outer end as well assegments of gear teeth 31 at their inner ends, the gear teeth facinginwardly toward the central axis of the housing 25. The chamber 27 canreceive an anchor actuating member 32 in the form of a sliding pistonhaving threads 33 on its outer periphery which drivingly engage the gearteeth 31 on each anchor arm. An annular flange 34 on the upper end ofthe piston 32 extends outwardly and a coil compression spring 35 can bearranged to press against the upper face of the flange. The piston 32 isretained in an upper position, where the anchor arms 28 are retracted,by a releasing member 36 which can take the form of a conventionalexplosive bolt or stud which is coupled to both the housing 25 and thepiston 32 and arranged to be electrically actuated in a conventionalmanner. In the upper position, the spring 35 is compressed and exertsdownward force on the piston 32. It will be appreciated that operationof the releasing member 36 will permit the coil spring 35 to move thepiston 32 downwardly within the chamber 27 and, due to theinterengagement between the piston threads 33 and the gear teeth 31, toswing the lower ends of the anchor arms 28 outwardly so that thegripping surfaces 30 can engage a well conduit wall of much larger boresize than the outer diameter of the housing 25.

Although the anchor arms 28 are particularly adapted to resist downwardmovement, it will be appreciated that the anchor mechanism could includea second set of arms, an actuating piston and spring, and a releasingmember of like construction to that shown, but oppositely disposed, sothat the anchoring mechanism can positively resist movement in eitherlongitudinal direction. Moreover, it will be equally appreciated thatinstead of a spring system for extending the arms 28 outwardly, ahydraulic system including a piston and an atmospheric chamber could beutilized for extending the anchor arms.

The actuating piston 32 can have axially extending bores 37 and 38formed therein which slidably receive an inflation pipe 39 and a ventpipe 40, respectively. The pipes 37 and 38 can be threadedly secured tothe housing 25 at the upper and lower ends of the chamber 27 and are inregistry with axial bores 19 and 23 in the housing 25. The bores 19 and23 are, in turn, axially aligned with the inflation and vent passages 21and 12, respectively. Suitable seals 45 can be appropriately positionedbetween the lower end surface of the housing 25 and the upper endsurface of the support tube 11 to prevent any fluid leakage from theinflation and vent passageways. A bore 41 in the housing 25 registerswith the inflation pipe 39 and extends upwardly to the uppermost endsurface of the housing and another bore 42 registers with the vent pipe40 and extends upwardly to a lateral or side port 43 which can belocated centrally of a reduced diameter upper section 44 of the housing25.

The pump section C includes a tubular case 46 which has a bore 47 formedin its lower end which is telescopically received over the upper reducedsection 44 of the anchor housing 25. A side port 48 in the wall of thecase 46 registers with the side vent port 43 to normally communicate thevent passageway with the well annulus. A releasable connection betweenthe case 46 and the anchor housing 25 is provided so that the pumpsection C can be selectively released for retrieval from the well.Although the releasable connection can take many forms, a simple shearscrew 50 is shown which can be ruptured by upward pull on the cable 10after the bag 14 has been inflated and the anchor arms 28 engaged withthe well conduit wall. Alternatively a pressure actuated releasing pincould be used which would release the case 46 from the anchor housing25. The pin could release at maximum inflation pressure to insure thatthe bag 14 is fully inflated.

The case 46 has upper and lower chambers 51 and 52, the lower chamber 52providing a fluid inlet and the upper chamber 51 adapted to contain asuitable pump and motor 53. The intake side of the pump is connected tothe lower chamber 52 by a suitable conduit 55 and the output side of thepump is provided with a conduit 56 which extends through the lowerchamber 152 for registry with the inflation passageway 41. A suitableseal 54 prevents fluid leakage at this point. Several side ports 57communicate the lower chamber 52 with the well annulus so the wellfluids can be used as the fluent medium for inflation of the packer bag14. If desired, a suitable filter or screen 58 can be provided in thelower chamber 52 to prevent undesired foreign particles in the wellfluids from entering the pump 53.

The prime mover for the pump can take any conventional form such as anelectric motor which can be supplied with power from the earths surfacevia the armored electrical cable 10. Operation of the motor will drivethe pump to displace well fluids into the packer bag 14 to inflate it. Aconventional one-way check valve 59 can be provided in the inflationpassageway 41 which permits well fluids to be pumped into the bag 14while preventing any return movement of the fluids. Moreover, it will beappreciated that a spring loaded secondary check valve (not shown) canbe provided so that inflation fluids can be withdrawn from the bag 14 ifdesired.

In operation, the tool can be lowered through relatively small sizetubing T and to a selected setting point within the larger casing P at alocation below the lowermost end of the tubing as shown in FIGURE 2. Theouter diameter of the tool can be, for example, 1 CD. for passingthrough small size tubing. The anchor arms 28 are initially in retractedpositions within the housing recesses 26 and the packer bag 14 is in itsretracted or folded condition. The vent passageway 12 is open to fluidflow.

When desired, electrical power is supplied from the earths surface viacable to operate the tool. The releasing member 36 is ruptured torelease the anchor actuating piston 32 for downward movement within thechamber 27. As the compression spring 35 presses the piston 32downwardly, the anchor arms 28 are pivoted outwardly until their outerends engage the casing P to anchor the tool against downward movement.The casing P can be of relatively large size, such as 5 /2 or 7". Themotor and pump 53 are also actuated to displace well fluids through theinflation passageway 21 and into the interior of the packer bag 14. Asfluid pressure builds up within the bag 14, the bag will expand as shownin FIGURE 2 until its outer periphery firmly seals against the wellcasing wall. The check valve 59 prevents any undesired return movementof inflation fluid so that a desired inflation pressure is maintainedwithin the bag 14.

After the bag has been fully inflated, the pump and motor 53 are shutoff and an upward pull on the cable 10 will shear the screw 50 torelease the pump section C for retrieval from the well. Thereafter, aconventional dump bailer (not shown) can be lowered through the tubing Tand a batch of cementitious or other hardenable material 60 deposited ontop of the bag 14 as shown in FIGURE 3. The material can be ofsufficient volume to provide an eflective bridging plug. Inasmuch as thevent passageway 12 is still open, any fluids being produced from zonesbelow the plug can pass through the vent passageway and into the wellconduit above the plug while the cement is hardening. Thus, producedfluids cannot act to form channels in the cement which destroy itseffectiveness in holding pressure.

After a sufficient length of time has elapsed for the cement to harden,a sleeve valve 62 having a connector head 65 for coupling to a suitablegrapple (not shown) can be lowered through the tubing T and positionedon the reduced diameter section 44 of the anchor housing 25 as shown inFIGURE 3. The sleeve valve 62 can have seal elements 63 and 64 adaptedfor positioning above and below the side vent port 43 to block any flowthrough the vent passageway. With the vent passageway 12 closed, theentire cross section of the casing P is packed off to block fluid flowin either direction.

A second apparatus constructed and arranged for performing the presentinvention is shown in FIGURE 4 and includes a bag section D coupled atits lower end to an inflating section E and coupled at its upper end toan anchor section F. A setting tool assembly G is releasably connectedto the anchor section F and the entire tool can be suspended on anarmored electrical cable 110.

The bag or plug section D includes a central support tube 111 having abore 112 therethrough which extends between a lower side port 113 andupper side ports 114. The support tube 111 can have a stepped portion115 around which the lower end of an expansible bag 116 can be mounted,the bag being secured to the section 115 by a suitable clamp 117. Theupper end of the bag 116 is similarly secured to a sliding sleeve 118which can move downwardly along the support tube 111 while fluid leakagetherebetween is prevented by a seal element 119. The bag 116 can besuitably constructed like its counterpart in the previously describedembodiment so as to be pliable as well as substantially impermeable. Thebag 116 can also have longitudinal or spiral folds (not shown) formedtherein for reducing its diameter while enabling it to be expanded to awell conduit diameter of several times its folded size.

The inflation section E includes a tubular housing 121 having a chamber122 therein adapted to contain an inflating medium 123 such as cement orplastic which is normally fluent and which is capable of hardening aftera predetermined span of time. The chamber 122 is placed in communicationwith the interior of the bag 116 by an inflation passageway 125. A fluiddisplacing piston 126, which can take the exemplary form of aconventional swab, is normally positioned at the lower end of thechamber 122 and is capable of displacing or forcing the fluent material123 through the inflation passageway 125 and into the bag 116 uponupward movement of the piston 126 within the chamber. A piston actuatingmember in the form of a pull wire 127 can be connected to the piston 126and extend upwardly into the support tube bore 112 through a packinggland 128, the pull wire 127 continuing upwardly through the supporttube bore 112 and then exiting through one of the upper vent ports 114.It will be appreciated that an upward pull on the actuating wire 127 canserve to move the piston 126 upwardly and displace the fluent material123 into the interior of the bag 116 to inflate it.

The anchor section F includes an annular shoulder or flange 130 whichcan be integrally formed on the support tube 111 and which carries aplurality of outwardly extendible anchor arms 131. The anchor arms 131are formed in pairs with each upper arm pivotally connected to a collar132 which is slidably mounted on the support tube 111. The lower one ofeach pair of arms 132 is pivotally connected to the flange 130 and thearms are additionally pivotally connected to one another. The outer endof each arm 131 is provided with wickers or teeth 134 adapted to biteinto and grip a well conduit upon being extended into engagementtherewith. Extension of the arms 131 can be eflected by advancement ofthe collar 132 along the support tube 111 toward the flange 130, causingthe arms 131 to pivot outwardly.

An annular setting head 135 is slidable on the support tube 111 abovethe collar 132 and a biasing spring 136 can be positioned intermediatethe head and collar to permit a limited amount of relative motiontherebetween. The setting head 135 has an internal annular recess 137therein forming an inclined surface which is cooperable with outerinclined surfaces of a locking slip 138, the locking slip 138 havingteeth 139 on its inner periphery engageable with the outer surface ofthe support tube 111. The locking slip 138 functions as a one-way clutchto permit downward movement of the setting head 135 relative to thesupport tube 111 for extending the anchor arms 131 and to preventconverse relative movement for maintaining the anchor arms extended.

The setting tool assembly G is conventional and familiar to thoseskilled in the art, an exemplary embodiment being shown in United StatesPatent No. 2,618,343. The tool can be selectively actuated by anelectrical signal through the cable 110 and is capable of exertingupward force on the support tube 111 through a threaded tension member140 and downward force on the setting head 135 through a compressionsleeve 141. Such forces can cause the setting head 135 to be advancedrelatively downwardly along the support tube 111 and toward the flange130 to expand the anchor arms 131 outwardly into engagement with thewell conduit wall. When a predetermined magnitude of setting force isreached, the tension member 140 will break in tension at a reduced neckportion 142. When the neck portion 142 breaks, the setting tool assemblyG is freed from its connection to the upper end of the support tube 111and can be hoisted 7 upwardly within the well by an upward pull exertedon the cable 110 at the earths surface.

For selectively closing the side vent ports 114, a sleeve valve 145 canbe positioned between the compression sleeve 141 and the support tube111 and adapted to slide on the support tube 111 adjacent to the sideports 114. Suitable seal elements 146 and 147 seal between the valve 145and the support tube 111. An upper portion 148 of the sleeve valve 145has its inner surface spaced laterally away from the outer surface ofthe support tube to form a passage space therebetween through which thepiston actuating wire 127 can extend. The terminal end of the wire 127can be connected to the setting tool tension member 140 by a suitablefastening device 149. The upper end of the vent valve 145 is providedwith a connector head 150 which is arranged so that when the settingtool assembly G is eventually removed from the well, a grapple or othersuitable means (not shown) can be lowered and connected to the connectorhead for pulling the sleeve valve 145 upwardly to a position where theseal elements 146 and 147 close off the vent ports 114.

In operation of the apparatus shown in FIGURE 4, the tool can besuspended on the cable 111) and lowered through a tubing string T to asetting point within a well casing P below the lowermost end of thetubing string. The bag 116 is in its folded condition and the entiretool can have a relatively small maximum outer diameter such as 1 forpassing through small size tubing. However, when the tool is positionedbelow the lower end of the tubing string, the bag 116 can be expanded topack off a relatively large size casing P which may be, for example, 5/2 or 7". An electrical signal applied to the cable 110 will activatethe setting tool assembly G for extending the anchor arms 131. Thecompression sleeve 141 is moved downwardly relative to the support tube111 to advance the setting head 35 toward the support tube flange 130.As this occurs, the anchor arms 132 are pivoted outwardly until theteeth 134 grip the well casing P as shown in FIG- URE 5. The teeth 139on the inner periphery of the locking slip 138 will grip the outersurface of the support tube 111 to hold the setting head 135 in thelowermost position to which it is moved, thereby locking the anchor arms131 in their extended positions. When a predetermined magnitude ofsetting force is built up in the setting tool tension member 141), thetension member will part at the reduced neck portion 142 to release thesetting tool assembly G for upward movement in the well bore. The pistonactuating wire 127 remains connected to the tension member 140, however.

To inflate and expand the bag 116, the setting tool assembly G is movedupwardly by upward pull on the cable 110 at the earths surface. Upwardmotion is translated by the wire 127 to the pump piston 126 and upwardmotion of the piston will displace fluent material 123 into the bag 116through the inflation passageway 125. As the bag 116 expands, thesliding sleeve 118 can move downwardly on the support tube 111 toaccommodate changes in length of the bag. The amount of upward pull onthe cable 110 controls the inflation pressure inside the bag 116 toinsure that an effective seal is formed against the casing wall. The bagsection D will not be moved upwardly by upward pull on the cable 110because of the holding action of the anchor arms 13.1.

Inflation pressure can be maintained within the bag 116 by applyingconstant tension to the cable 11d and can be maintained for a suflicientlength of time to allow the fluent material 123 to harden into a solidmass. When the material has hardened within the bag 116, an overpull onthe cable 110 will serve to part the wire 127 and the setting toolassembly G can be withdrawn from the well. It will be noted that duringthe entire time that the fluent material 123 is hardening, the ventports 113 and 114 are open. Accordingly, if a zone below the plug isproducing fluid, the fluid can pass through the bag 116 via the supporttube bore 112 and the fluid will not disturb the bag 116. When desired,a suitable grapple (not shown) can be lowered through the tubing stringT and coupled to the connector head 156 so that the vent valve can bemoved to its upper position for closing the vent ports 114 to fluid flowas shown in FIGURE 6. The vent valve 145 is pressure balanced so that itwill not open in response to pressure from above or below.

If desired, a batch of additional cementitious material 152 can bedeposited by a conventional dump bailer (not shown) on top of the bag116 and allowed to harden to provide for additional overall length ofthe plug. If additional material is used, the vent valve 145 can be leftin its open position to insure that the material will remain undisturbedas it hardcns. The valve can then be closed as previously described. Useof additional cementitious material on top of the bag 116 can furtherinsure that the plug will remain immovable in the well and can withstandhigh pressure differentials acting from either direction.

A third apparatus constructed and arranged for performing the presentinvention is illustrated in FIGURE 7 and includes a control section Hadapted for suspension on an electrical wire-line or cable (not shown).The control section H is coupled to a pump section I. A valve assembly Lis coupled to the lower end of the pump section I and the valve assemblyis in turn connected to a bridge plug assembly M. At the lower end ofthe bridge plug assembly M is a vent valve section N.

The control section H includes a tubular case 212 having alongitudinally extending chamber 213 therein. A piston 214 is movablyreceived within the chamber 213 and a rod 215 connected to the pistonextends downwardly through a bore 216 which opens axially into thechamber 213. The upper portion of the chamber 213 is arranged to receivea suitable hydraulic fluid, and a coil compression spring 218 isarranged in the lower portion of the chamber to urge the piston 214 andthe rod 215 upwardly. Several side ports 219 in the wall of the case 212below the piston 214 enable fluid pressures within the chamber 213 to bebalanced with hydrostatic well fluid pressures as the tool is loweredinto a fluid filled well bore. To permit placement of hydraulic fluidinto the upper portion of the chamber 213, a one-way check valve 221 inan entry passage 221 is provided. An exit passage 222 extends from thechamber 213 to the exterior of the case 212 and has a remotelycontrollable valve 223 therein, such as a conventional solenoid operatedvalve, which normally prevents discharge of hydraulic fluid from thechamber so that the piston 214 and the rod 215 cannot move upwardlyunder the influence of the upward force being exerted by the coil spring218.

The piston rod 225 extends downwardly through the bore 216 to a locationwithin a recess 225 where it can operate a latch device. The latchdevice includes a plurality of upwardly extending, inwardly biasedspring fingers 227, the spring fingers terminating in enlarged headportions 228. When the parts are in the relative positions shown inFIGURE 7, the head portions 228 are held outwardly by the rod 215 inengagement with a shoulder 230 formed by the recess 225. However, itwill be appreciated that removal of the rod 215 from behind the headportions 228 will permit them to spring inwardly and out of engagementwith the shoulder 230. The retention and release of the spring fingers227 from the recess 225 controls the operation of the pump section I.

The pump section I includes a cylindrical housing 232 coupled at itsupper end to the control section H and at its lower end to a bailercylinder 237. The housing 232 has a bore 233 in which a weighted bodymember 234 is movable. The weighted member 234 can be an elongatedtubular member formed with a rod 235 extending upwardly from its upperend, the rod having the previously described spring fingers 227connected to its upper end and extending into the recess 225. A coilcompression spring 236 can surround the rod 235 with its upper endpressing against the upper end of the bore 233 and its lower endpressing against the upper surface of the weighted member 234.

Positioned within the bore of the cylinder 237 and spaced below thelower end of the weighted member 234 is a piston 238 having an elastomerswa cup 239 connected to its lower end. The swab cup 239 defines theupper end of a fluent material chamber 240 Within the bore of thecylinder 237 and which is adapted to contain a suitable material, suchas cement, which has liquid or flowable properties for a predeterminedlength of time and which is thereafter capable of hardening or settingup to form a solid mass. The lower end portion of the cylinder 237 has areduced diameter section 242 which is sized for telescopic receptioninto a bore 243 formed in a tubular housing 244 which is a component ofthe valve assembly L. A shearable pin member 245 releasably couples thecylinder 237 to the valve housing 244.

The valve housing 244 has a central chamber 246 formed therein withstepped wall surfaces providing a first larger diameter portion 247 anda second smaller diameter portion 248. A valve element 250 is slidablyreceived within the chamber 246, the valve element being in the form ofa sleeve piston having an annular head 251 received in the first chamberportion 247, the valve element further having a tubular portion 251extending downwardly into the second chamber portion 248. An O-ring seal252 seals between the head portion 251 and the wall of the enlargedchamber portion 247, and a second O-ring seal 253 can be positioned toseal between the tubular portion 251 and the wall of the second chamberportion 248.

The valve element 250 further has a central bore 254 extendingthroughout its length which sealingly receives .a downwardly extendingtubular member 255. The tubular member 255 is, in turn, connected to theupper end portion of a smaller diameter vent tube 256. The bores of thevent tube 256 and the tubular member 255 form a vent passageway 257which is open to the exterior of the tool by a side port 258. The valvehousing 244 has an axially extending oflset bore 2611 which is alignedwith the bore 241 which communicates with the fluent material chamber240 to provide an inflation passageway. It will be appreciated that thevalve element 250 is arranged to prevent flow of the fluent materialfrom the cylinder 237 as long as the valve element is in its upperposition as shown in FIGURE 7. In this position, the valve element 251)is retained by a shear screw 261. A compressed coil spring 262 isarranged to exert downward force on the valve element 250 for moving itto a lower position within the chamber 246 when the shear screw fails.As the valve element 250 moves downwardly within the chamber 246, thehead portion 252 can tele scope away from the tubular extension 255 toplace the passage 241 in communication with the annulus 263 between thesleeve 251 and the vent tube 256, thereby permitting the fluent materialwithin the chamber 240 to flow downwardly through the valve element 250.

The bridge plug assembly M includes a tubular body or support 270 whichcan be integrally formed with, and extend downwardly from, the valvehousing 244. An expansible bag 271 is mounted around the support 274with its lower end portion secured to a lower sliding sleeve 272 and itsupper end similarly secured to an upper sliding sleeve 273. Suitableseals 274 and 275 fluidly seal between the sleeves and the support tube2741 to prevent any fluid leakage from the bag 27.1. The upper sleeve273 can be initially restrained against sliding motion relative to thesupport 278 by locating the inner portion of the seal element 275 withina peripheral groove around the support 270 so that the seal elementitself can yielda'bly resist relative motion between the sleeve and thesupport.

The vent passageway 257 extends axially in the support 276 from achamber 277 at the lower end portion of the support to the bore of thevent tube 256 at the upper end portion of the support. The chamber 277is normally in communication with the Well annulus by way of side ports278 so that well fluids can pass freely through the vent passageway 257.A vent valve 279 in the form of a sleeve is provided for selectivelyclosing olf the vent passageawy 257 to fluid flow and is normallypositioned at the lower end of the chamber 277 below the side ports 278.Seal elements 280 and 281 around the outer periphery of the valve 279fluidly seal against the wall surfaces of the chamber 277 and arepositioned so that when the valve is moved to its upper position, theseal elements will block fluid flow through the side ports 27% and thusthe vent passageway 257. A valve actuating wire 282 can be suitablyconnected to the vent valve 27? and extend upwardly through the ventpassageway 257 to a location within the lower end portion of the bailerhousing 232 where it can be securely attached by any suitable means suchas a threaded plug (not shown) extending through the wall of the lowersection. It will be appreciated that an upward pull on the wire 282 canshift the valve 279 to its upper position for closing the ventpassageway 257 to fluid flow. It will be noted that the seal arrangementof the sleeve valve 279 makes the valve pressure balanced so that itwill not be moved in response to fluid pressure from either above orbelow.

An annular inflation passageway 285 extends in the upper portion of thesupport 270 and communicates with the interior of the bag 271 viaseveral lateral ports 286 and is coextensive with the annulus passageway263 between the valve element 250 and the vent tube 256. Accordingly,fluent material which passes through the valve element 250 can enterinto the interior of the bag 271 to expand it against the surroundingwell conduit wall. If desired, a rubber bumper sub 287 can form thelowermost end portion of the tool to insulate the tool from shock loadswhich may be imposed upon it while lowering into the well.

In operation, the tool is prepared for lowering into the well bylatching the weighted member 234 in its upper position as shown inFIGURE 7 and filling the control chamber 213 above the release piston214 with a suitable hydraulic fluid so that the rod 215 is properlypositioned behind the latch fingers 2127. The compression spring 236 isinitially in a compressed condition and exerts downward force on theweighted member 234. The inflation valve element 250 is secured in itsupper closed position by the shear screw 261 and the chamber 240 withinthe cylinder 237 can be filled with predetermined volume of initiallyfluent but hardenable material such as cement. The vent valve actuatingwire 276 is appropriately secured so that the vent valve 279 is in alower position where the side ports 278 are open.

The tool is then lowered downwardly into the well on the electricalcable through the tubing T and to a selected setting point within thewell casing P below the lowermost end of the tubing as shown in FIGURE8. At setting depth, an electrical signal initiated at the earthssurface will open the solenoid valve 223 in the control section H so thehydraulic fluid can exit from the chamber 213. As the fluid exits, theforce of the spring 218 can move the piston 214 and the rod 216upwardly. As the rod 216 moves upwardly, the latch fingers 227 are freedto spring inwardly and release from the recess 225.

When the rod 216 is released, the force of the spring 236 acts toaccelerate the weighted member 234 downwardly so that it can strike thepiston 238 with a jarring force. This coaction creates a substantialpressure surge in the fluent material within the chamber 240 which actsthrough the passageway 241 on the upper face of the valve element 250,thereby imparting a substantial force to the valve element whichfunctions to shear off the valve retaining screw 261. Release of theretaining screw 261 permits the valve element 250 to move downwardly toits lower position shown in FIGURE 8 so that the fluent material canflow through the annulus 263, the passageway 285, the ports 286 and intothe interior of the bag 271.

The weighted member 234 will then rest on the piston 238 and tend togravitate downwardly, thereby forcing the swab cup 239 downwardly andgenerating pressure within the chamber 240 to displace fluent materialinto the bag 271. It will be appreciated that the inflation pressurewhich can be applied to the bag 271 is a function of the weight of theweighted member 234 and the crosssectional area of the swab cup 239. Theweighted member 234 can be constructed of suitable heavy or dense metalsuch as tungsten carbide and be sized so that a suitable inflationpressure, such as, for example, 15-25 p.s.i. can be developed within thebag 271 to expand it into effective sealing engagement with the wellconduit wall as shown in FIGURE 8.

After the bag 271 is fully inflated, it forms, in effect, a platform inthe well bore on which an additional volume of material can bedeposited. This can be accomplished by manipulation of the toolincluding an upward pull on the cable to shift the support 270 upwardlyrelative to the bag 271, thereby exposing the inflation ports 286 to thewell annulus above the bag as shown in FIGURE 9. Movement of theinflation ports 286 above the seals 275 on the sliding sleeve 273 trapsthe inflation pressure within the expanded bag 271 and permits dumpingthe remainder of the cementitious material within the chamber 240 on topof the bag 271. With the tool parts in the relative positions shown, asuflicient period of time is allowed to pass such that the material bothwithin the bag 271 and on top of the bag can harden into a solidifiedmass, the material on top of the bag increasing the overall length ofplug formed and enhancing the plugs ability to withstand high pressurefrom above or below.

During the time that the material is hardening, the vent passageway 257remains in open condition as shown in FIGURE 8 so that any producedfluids entering the casing P from below the bag can pass upwardlytherethrough and enter the well annulus above the plug through the sidevent port 258. Accordingly, it will be appreciated that such fluids willhave no tendency to form channels either around the bag 271 or throughthe material on top of the bag, which disturbances may otherwise destroythe effectiveness of the plug to hold pressure. When the plug is fullyformed, an upward pull on the cable will serve to shear the releasingpin 245 to disconnect the pump and control sections H, J from the packerand valve sections M, L and permit retrieval of the pump and controlsections from the well. The initial upward movement of the pump sectionimparts upward movement to the valve actuating wire 282 which, in turn,moves the vent valve 279 to its upper closed position. Continued upwardmovement will cause the wire 282 to part as shown in FIGURE 9, leavingthe vent valve 279 in a closed position to block all vertical movementof fluids within the well casing P. The bailer and control sections Jand H can then be withdrawn to the earths surface through the tubing T.

New and improved methods and apparatus have been disclosed foreffectively plugging a well conduit. In accordance with the presentinvention, the plug can be lowered through small tubing and then set orformed in a large size casing or open hole without removing the smallertubing from the well. The invention is arranged in a manner forcontrollably bypassing or venting fluid flow while the plug is formingto prevent disturbance of the plug. Accordingly the plug will beeffective in holding pressure differentials which may be imposed uponit.

Since certain changes and modifications may be made in the disclosedembodiments of the invention without departing from the conceptsinvolved, it is the aim of the appended claims to cover all such changesand modifications which fall within the true spirit and scope of thepresent invention.

We claim:

1. A method for forming a pressure bridge in a well conduit comprisingthe steps of: lowering an inflatable packer into a well through a tubingstring and to a setting point in a well conduit below the lowermost endof the tubing string; selectively actuating a pump means from the earthssurface to displace an inflating medium into the packer, therebyexpanding the packer to a size several times its unexpanded size andagainst the surrounding well conduit wall to form a plug in the wellconduit; temporarily venting the packer so that well fluid can passthrough the packer from one side to the other even though the packer isexpanded; releasing the pump means from the expanded packer; retrievingthe pump means to the earths surface; and closing the vent so that thepacker is effective to prevent fluid flow in either longitudinaldirection past its sealing point.

2. The method recited in claim 1 further including the step of placing acementitious material on top of the expanded packer and allowing thematerial to harden before closing the vent,

3. The method recited in claim 1 further including the step of anchoringthe packer against movement in the well conduit.

4. A method for forming a pressure bridge in a well conduit comprisingthe steps of: lowering an inflatable packer and pump means into a wellthrough a tubing string and to a setting point in the well conduit belowthe lowermost end of the tubing string; selectively actuating the pumpmeans from the earths surface to displace an inflating medium into thepacker, thereby expanding the packer to a size several times itsunexpanded size and against the surrounding well conduit wall to form aplug in the well conduit; temporarily venting the packer so that fluidcan pass through the packer from one side to the other; releasing thepump means from the expanded packer; retrieving the pump means to theearths surface; then lowering a valve means into the well for closingthe vent; and closing off the vent with the valve means so that thepacker is effective to prevent fluid flow in either longitudinaldirection past its sealing point.

5. The method of claim 4 including the additional steps of anchoring thepacker against movement in the well conduit.

6. Apparatus for bridging a well conduit below the lower end of a tubingstring in a well conduit comprising: a bridging member adapted to passthrough a tubing string and expandable in a well conduit to close offthe cross section of the well conduit, said bridging member having alongitudinally extending central support with a vent passagewaytherethrough which is arranged to provide communication across saidbridging member, the upper end of said vent passageway terminating inlaterally extending sort means in the wall of said support, said supportbeing adapted for receiving a closure member which spans said port meansto close off said passageway.

7. Apparatus for bridging a well conduit below the lower end of a tubingstring in a well conduit comprising: a bridging member including anexpansible packing element adapted to pass through a tubing string andexpandable in a well conduit to close off the cross section of the wellconduit, means detachably coupled to said bridging member for expandingsaid packing element, said bridging member having a longitudinallyextending support member with a vent passageway arranged to providecommunication across said bridging member, one end of said passagewayterminating in laterally extending port means, and sleeve valve meansfor closing off said port means.

8. A well apparatus for insertion into a well bore through a first wellconduit and adapted for expansion to plug a second well conduit having arelatively large bore size, comprising: a support tube; an inflatableexpansible member mounted around said support tube and adapted for awide range of expansion upon inflation thereof; a vent passagewaythrough said support tube and extending from a location below saidexpansible member to a location above said expansible member so thatWell fluids can pass longitudinally through said expansible member inits inflated condition; pump means for displacing fluid into saidexpansible member to inflate it; an inflation passageway in said supporttube extending between said pump means and the interior of saidexpansible member; means for releasably coupling said pump means to saidsupport tube so that said pump means can be released and retrieved tothe surface after inflation of said expansible member; and valve meansfor selectively closing said vent passageway.

9. A well apparatus adapted for insertion into a Well bore through afirst smaller well conduit and for expansion to plug off a second largerwell conduit, comprising: a support tube; an inflatable expansiblemember mounted around said support tube and arranged for a wide range ofexpansion upon inflation thereof; a vent passageway in said support tubeand extending between locations on opposite sides of said expansiblemember so that fluid can pass therethrough; pump means for inflatingsaid expansible member; an inflation passageway connecting said pumpmeans and said expansible member; control means for enabling remote andselective operation of said pump means, said control means beingcontrollable from the earths surface; means for releasably coupling saidpump means to said support tube so that said pump means can be releasedand then retrieved from the surface after functioning to inflate saidexpansible member; and valve means operable from the earths surface forselectively closing said vent passageway.

10. The apparatus of claim 9 further including extendible meansconnected to said support tube and movable outwardly thereof foranchoring said apparatus in the well conduit.

11. The apparatus of claim 10 wherein said extendible means comprisearms which are pivotally mounted relative to said support tube, theouter ends of said arms have conduit gripping portions.

12. A well apparatus for insertion into a well bore comprising: asupport tube; an inflatable expansible member mounted around saidsupport tube and adapted for a wide range of expansion upon inflationthereof; a vent passageway in said support tube extending betweenlocations above and below said expansible member; an inflationpassageway in said support tube communicating with the interior of saidexpansible member and through which a fluent medium can be displaced forexpanding said expansible member; pump means coupled to said supporttube and adapted to displace a fluent medium through said inflationpassageway; means for releasably coupling said pump means to saidsupport tube; normally retracted anchor means extendible outwardly ofsaid support tube for anchoring said support tube in a well conduit;selectively operable means for extending said anchor means; and valvemeans for closing 011 said vent passageway.

13. The apparatus of claim 12 wherein said vent passageway terminatesabove said expansible member in a laterally extending port means, andsaid valve means includes a sleeve member having seal means engageablewith said support tube above and below said port means.

14. Packer apparatus for use in bridging a Well conduit, comprising: asupport; an expansible packing sleeve mounted on said support and havinga wide range of expansion whereby said packing sleeve can be passedthrough a relatively small diameter tubing string and then expanded topack-oft a larger diameter well conduit below the lower end of thetubing string; means releasably coupled to said support for expandingsaid packing sleeve, said packing sleeve, when expanded, forming abridge in the well bore for supporting a column of cementitious materialthereabove; a flow passage through said support extending between alocation in communication with the well bore below said packing sleeveto a location in communication with the well bore above the column ofcementitious mateiral, whereby well fluids flowing through said passagecannot disturb the cementitious material as it hardens; and pressurebalanced valve means for closing oflf said flow passage after thecementitious material has hardened.

15. The apparatus of claim 14 wherein one of said locations incommunication with the well bore is formed by a laterally extending portin said support; said valve means including a sleeve member having sealsengageable with said support above and below said port.

16. The apparatus of claim 14 wherein said expanding means includesmeans for developing a fluid pressure inside said sleeve member which isgreater than the fluid pressure in the well bore outside said sleevemember.

References Cited UNITED STATES PATENTS 2,222,750 11/1940 Litolff 1661872,618,344 11/1952 Turechek et al. 166-187 2,629,446 2/1953 Freling et al166187 2,717,644 9/1955 Bell et a1. 166l87 2,769,498 11/1956 Huber166187 2,978,029 4/ 1961 OReilly et a1 166187 3,066,739 12/ 1962Saurenman et a1. 166187 JAMES A. LEPPINK, Primary Examiner US. Cl. X.R.166-101, 187, 315

